The objective of this application is to analyze the promoter for the FSHR gene for cis-acting elements and, ultimately, transcription factors that interact to mediate hormonal responsiveness and Sertoli cell-specific expression of this gene. In aim 1, scanning mutagenesis of the proximal promoter of the FSHR gene will be used to identify DNA response elements important for expression in a Sertoli cell line and primary cultures of Sertoli cells. In aim 2, the effects of FSH, EGF, and TGF-beta on the expression of the FSHR gene will be studied. First, the mRNA encoding the FSHR following treatment of primary cultures of Sertoli cells with either FSH, EGF, or TGFbeta will be analyzed. Second, the transcriptional response of the FSHR promoter to these same substances will be addressed by transient expression assays in Sertoli cells. Third, co-expression of FSHR promoter constructs with constitutively active forms of intracellular kinases that are involved in either FSH, EGF, or TGFbeta signal transduction will be performed.